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Analysis of a method to measure the dodecapole component of the LHC triplet magnets with a wobbling closed bump

Due to finite manufacturing tolerances the triplet quadrupoles used in the interaction regions of LHC will have non-vanishing multipole errors which need to be measured and corrected in order to guarantee sufficient dynamic aperture at collision energy. Here we discuss a method to measure the unwant...

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Autor principal: Ziemann, Volker
Lenguaje:eng
Publicado: 2002
Materias:
Acceso en línea:http://cds.cern.ch/record/560947
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author Ziemann, Volker
author_facet Ziemann, Volker
author_sort Ziemann, Volker
collection CERN
description Due to finite manufacturing tolerances the triplet quadrupoles used in the interaction regions of LHC will have non-vanishing multipole errors which need to be measured and corrected in order to guarantee sufficient dynamic aperture at collision energy. Here we discuss a method to measure the unwanted multipole components by oscillating a closed orbit bump in the interaction region and observing the orbit at pickups outside the bump. The beam's response will contain very weak signals at harmonic frequencies of the sinusoidal excitation. Even though the amplitude of the harmonic signal will be below the resolution of the position monitor system, it can be made visible by adding noise to the original pickup data and subsequent careful filtering and averaging. We use a simple computer model to simulate the oscillating bump that generates pickup signals and then analyze those in a sophisticated signal processing chain in order to retrieve the magnitude of the unwanted multipole components.
id cern-560947
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2002
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spelling cern-5609472023-05-05T13:08:17Zhttp://cds.cern.ch/record/560947engZiemann, VolkerAnalysis of a method to measure the dodecapole component of the LHC triplet magnets with a wobbling closed bumpAccelerators and Storage RingsDue to finite manufacturing tolerances the triplet quadrupoles used in the interaction regions of LHC will have non-vanishing multipole errors which need to be measured and corrected in order to guarantee sufficient dynamic aperture at collision energy. Here we discuss a method to measure the unwanted multipole components by oscillating a closed orbit bump in the interaction region and observing the orbit at pickups outside the bump. The beam's response will contain very weak signals at harmonic frequencies of the sinusoidal excitation. Even though the amplitude of the harmonic signal will be below the resolution of the position monitor system, it can be made visible by adding noise to the original pickup data and subsequent careful filtering and averaging. We use a simple computer model to simulate the oscillating bump that generates pickup signals and then analyze those in a sophisticated signal processing chain in order to retrieve the magnitude of the unwanted multipole components.CERN-SL-2002-018-APCERN-TSL-NOTE-2002-54oai:cds.cern.ch:5609472002-05-13
spellingShingle Accelerators and Storage Rings
Ziemann, Volker
Analysis of a method to measure the dodecapole component of the LHC triplet magnets with a wobbling closed bump
title Analysis of a method to measure the dodecapole component of the LHC triplet magnets with a wobbling closed bump
title_full Analysis of a method to measure the dodecapole component of the LHC triplet magnets with a wobbling closed bump
title_fullStr Analysis of a method to measure the dodecapole component of the LHC triplet magnets with a wobbling closed bump
title_full_unstemmed Analysis of a method to measure the dodecapole component of the LHC triplet magnets with a wobbling closed bump
title_short Analysis of a method to measure the dodecapole component of the LHC triplet magnets with a wobbling closed bump
title_sort analysis of a method to measure the dodecapole component of the lhc triplet magnets with a wobbling closed bump
topic Accelerators and Storage Rings
url http://cds.cern.ch/record/560947
work_keys_str_mv AT ziemannvolker analysisofamethodtomeasurethedodecapolecomponentofthelhctripletmagnetswithawobblingclosedbump